<?php
set_time_limit(0);
//把该文件放到WEB根目录下，运行一次可以清除当前目录及所有子目录中所有文件的BOM Header。
//经测试，安全。
if (isset($_GET['dir'])){ //设置文件目录
	$basedir=$_GET['dir'];
}else{
	$basedir = '.';
}
$auto = 1;
checkdir($basedir);
function checkdir($basedir){
	if ($dh = opendir($basedir)) {
  		while (($file = readdir($dh)) !== false) {
   			if ($file != '.' && $file != '..'){
    			if (!is_dir($basedir."/".$file)) {
     				echo "filename: $basedir/$file ".checkBOM("$basedir/$file")." <br>";
    			}else{
     				$dirname = $basedir."/".$file;
     				checkdir($dirname);
    			}
   			}
  		}
	closedir($dh);
	}
}

function checkBOM ($filename) {
	global $auto;
	$contents = file_get_contents($filename);
	$charset[1] = substr($contents, 0, 1);
	$charset[2] = substr($contents, 1, 1);
	$charset[3] = substr($contents, 2, 1);
	if (ord($charset[1]) == 239 && ord($charset[2]) == 187 && ord($charset[3]) == 191) {
  		if ($auto == 1) {
   			$rest = substr($contents, 3);
   			rewrite ($filename, $rest);
  			return ("<font color=red>BOM found, automatically removed.</font>");
  		} else {
   			return ("<font color=red>BOM found.</font>");
  		}
	}else return ("BOM Not Found.");
}

function rewrite ($filename, $data) {
	$filenum = fopen($filename, "w");
	flock($filenum, LOCK_EX);
	fwrite($filenum, $data);
	fclose($filenum);
}
?>
